OLD HealthRider Glider

I have an old HealthRider Glider that is at least 20 to 25 years old. Probably the first model they made. Still works as well as it did when I first bought it and I use it at least 3 times per week. The problem is I've lost a couple of the rubber caps on the feet and my wife ways as it moved around it messes up the floor. QUESTION: Are parts still available for a machine that old? If so, where? PS: It has no model number or serial number on it anywhere. Thanks.